Grounding of metal tanks 1

[kptx171]

I have to design a grounding system for four steel tanks at ground level.System parameters: 480v/277v,fault level 50 KA at 480V.The tanks are of 20 ft dia and placed at 50 ft center to center to each other.I need yr suggestions for the size cable ,no.and dia of ground rods,ground grid information.

 

[davidbeach]

What research have you done, and what solutions have you tentatively come up with? This site is not a source of free engineering.